JP3520772B2 - Lamination mold and molding method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminating and molding die for molding a skin laminating resin molded article by integrating a skin material having a resin decorative layer with a core molten resin by injection molding or press molding. Also, the present invention relates to a method of laminating and forming a skin.

[0002]

2. Description of the Related Art In recent years, resin molded products used in automobiles, home appliances, building materials, etc. have been given added value such as decorativeness and touch to enhance the quality and added value of molded products, and to reduce the molding process. In order to reduce the cost, it is often produced by a two-layer molding method in which a surface material having a resin decorative layer is fusion-bonded to the surface of the core layer. As a skin material,
The outermost layer is made of a resin sheet, a resin woven cloth, a resin woven cloth, a resin nonwoven cloth, or a decorative layer lined with a foamed resin layer. As the two-layer molding method, a method using an injection molding machine and a method using a press molding machine described below are mainly used.

(1) Method for performing two-layer molding using an injection molding machine A skin material is set between both molds which have been opened, and the mold is closed to apply a mold clamping force, and then the skin material is removed. A molten resin to be a core layer is injected and filled by an injection device into a mold cavity space formed by the mold. After the holding pressure and cooling are completed, the mold is opened and the molded product is taken out. (2) Method of performing two-layer molding using a press molding machine A skin material is set between the opened molds, and the molds are closed to maintain a predetermined mold opening amount between the molds. Molten resin to be a core layer is discharged by a resin melting unit into a mold cavity space formed by the skin material and the mold. Both molds are pressed with a mold to exert a mold clamping force, and after cooling for a predetermined time, the mold is opened and a molded product is taken out.

[0004]

However, such a conventional method has the following problems. (1) A skin material having a resin sheet as the outermost layer is subjected to a high temperature and high pressure state by the core material resin during injection filling of the molten resin to be the core layer or during mold closing press to completion of cooling. To be done. Therefore, minute irregularities (scratches) existing on the surface of the mold are transferred to the surface of the resin sheet, and a new surface defect is generated by laminating and molding.
In order to avoid this phenomenon, it is necessary to improve the finishing accuracy of the die surface, which has been a factor of increasing the die manufacturing cost. Even if molding is performed using a mold with a good surface finish, it is possible to eliminate the surface pattern (air mark) that occurs when air is entrapped between the resin sheet on the surface of the skin material and the mold cavity surface. could not.

(2) Further, dust floating in the air adheres to the resin sheet or the mold cavity surface during molding,
Since this dust is transferred to the surface of the molded product during laminating and forming a surface defect, it is difficult to obtain a completely good product. (3) Although it is effective to use a clean room or a clean booth to eliminate the influence of dust, it is economically unfeasible to apply the clean room to the laminating and molding since it increases the cost. Therefore, the surface defects caused by the transfer of dust to the surface of the molded product during laminating and the surface defects due to air marks are
Up until now, they have given up as unavoidable and have been satisfied with the above-mentioned defective skin-integrated laminated molded article although they are unsatisfactory.

(4) On the other hand, in the case of a skin material having a decorative layer such as a resin woven cloth, a resin napped woven cloth, or a resin non-woven cloth as the outermost layer, injection filling or molding of a molten resin to be a core layer Since the high temperature and high pressure state is applied to the skin material by the core material resin from the time of closing press to the completion of cooling, there is a problem that the original texture of the skin material cannot be maintained due to hair collapse and loss of touch. Further, even in the case of the skin material in which the decorative layer is lined with the foamed resin layer, the skin material is in a high temperature and high pressure state due to the core material molten resin during injection filling of the core layer molten resin and completion of cooling from the mold closing press However, the original thickness of the foam layer was greatly reduced, and only a molded product with impaired cushioning properties was obtained. For this reason, it is necessary to use a thick skin material with a foam layer in advance in anticipation of a decrease in the foam layer, which has been a factor of increasing the cost of the skin material.

[0007]

In order to solve the above-mentioned problems, in the present invention, in the first invention, the structure is provided in a mold cavity composed of a movable mold and a fixed mold. , A skin material having a resin decorative layer as the outermost layer or a skin material in which the decorative layer is lined with a foamed resin layer is integrated with the core material molten resin by injection molding or press molding to form a skin-bonded resin molded product In the die for laminating molding,
The surface of the mold cavity of the movable mold is divided into a plurality of movable plates, and a movable core is fixed to the side of the movable plate opposite to the mold cavity surface, and a working fluid is introduced before and after the movable core. The movable plate is movable back and forth. In the second invention, a skin material having a resin decorative layer as an outermost layer or a skin material in which the decorative layer is lined with a foamed resin layer is integrated with a core material molten resin by injection molding or press molding to form a skin. In the laminating molding method for molding a laminated resin molded article, as the decorative layer or the foamed layer, a material having a glass transition temperature equal to or lower than the maximum temperature that the decorative layer or the foamed layer receives during mold clamping is used. When the temperature of the molten resin of the core material or the temperature of the skin material reaches a preset temperature during mold clamping, all movable cores having a cavity surface are retracted, and the cavity surface and the A gap is provided between the skin material and the skin material. Further, in the third invention, the gap in the second invention is set to 0.05 mm or more when the decorative layer is a resin sheet, and the decorative layer is a woven fabric or a resin raised woven fabric. In the case of a cloth, a resin sheet made of a non-woven fabric made of resin or a skin material in which a decorative layer is lined with a foamed resin layer, the thickness is 0.5 times or more the thickness of the decorative layer.

[0008]

By carrying out the present invention, the following preferable molding can be carried out. In the skin-integrated laminating molding, the skin material is heated by the amount of heat of the core material molten resin immediately after injection filling, but the skin material is also cooled with the progress of cooling and solidification of the entire molded product thereafter. That is, in the ordinary laminating molding, the resin sheet, the resin woven cloth, the resin woven cloth with the resin raised fabric, the resin nonwoven nonwoven skin sheet or the decorative layer constituting the skin material decorative layer is lined with the foamed resin layer. The skin material continues to decrease in temperature after reaching the maximum temperature. During this time, when the skin material temperature reaches the maximum temperature, the decorative layer or the foam layer pressed against the mold cavity surface is deformed by the pressure. Moreover, when the temperature of the decorative layer or the foamed layer becomes lower than the glass transition point due to the subsequent cooling, the molecular motion is frozen, so damage and surface defects such as hair tumble and loss of tactile feeling existing at the time of deformation. Will not be improved thereafter and will remain on the surface of the molded product.

On the other hand, in the present invention, the same applies until the temperature of the skin material constituting the decorative layer reaches the maximum temperature until it is pressed against the cavity surface of the mold to be deformed. When the temperature of the material reaches a preset temperature, the mold clamping force is removed and a gap corresponding to the predetermined set mold opening amount is opened between the skin material and the mold cavity surface to make the predetermined setting. I tried to hold it for a while. By doing this,
The temperature of the skin material can be raised again to the maximum temperature received by the skin material during mold clamping due to the presence of the heat insulating layer (gap) and supplementation of the heat amount from the core material molten resin. Since the glass transition point of the surface material decorative layer is selected to be equal to or lower than the maximum temperature that the surface material receives during mold clamping, the frozen molecular motion is released and the damaged part of the decorative layer is elastically affected. Can be self-healing. As a result, when the outermost layer is a decorative layer of a resin sheet, surface defects such as dust transfer in the mold cavity and air marks cause the outermost layer to be a resin woven fabric, a resin woven fabric with a nap, or a resin In the case of a non-woven fabric, it is possible to prevent hair loss and loss of touch, or in the case of a skin material in which the decorative layer is lined with a foamed resin layer, the loss of touch and texture of the skin material due to the reduction of the thickness of the foam layer can be prevented. Therefore, it is possible to stably supply an extremely high quality skin-integrated laminated molded product.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described in detail below with reference to the drawings. 1 to 4 relate to an embodiment of the present invention, FIG. 1 and FIG. 2 are overall configuration diagrams of a bonding and molding die, FIG. 3 is a flowchart of a molding process of laminating with integral skin, and FIG. FIG. 6 is an explanatory view showing temperature changes of the core material and the skin material of FIG.

As shown in FIG. 1, a laminating and molding die 100 according to the present invention comprises a movable die 1, a fixed die 2, and movable plates 11 and 1 which form a cavity surface of the movable die.
2, 13 and hydraulic cylinders 21, 22 and 23 that move the movable plate back and forth. Movable plates 11, 12, 13 that form the cavity surface of the movable mold 1
A temperature sensor (not shown) is attached to the motor (a movable plate, a hydraulic cylinder, and the like constitute a movable core). As a matter of course, the movable core is also installed in the direction perpendicular to the paper surface of FIG. 1 (not shown). It should be noted that the present bonding and molding die 100 is used by being attached to an injection molding machine or an injection press molding machine.
1 shows a state where the movable plates 11, 12 and 13 are moving forward (during injection filling), and FIG. 2 shows a state when the movable plates are retracted (when a gap for heat insulation is secured) in FIG. It is shown.

Next, the structure of the mold according to the embodiment of the present invention will be described. Since the location where the skin material is attached to the surface of the molded product has been determined during product design, the number of divisions of the movable core to be installed is determined. At this time, it is necessary to divide the moving direction of the movable plate into a mold clamping direction and a direction perpendicular to the mold clamping direction. With the conventional method of securing the gap only by the mold clamping operation, the gap cannot be secured in the plane parallel to the mold clamping direction, but it is possible with the configuration using the movable core of the present invention. Since this movable plate receives the resin pressure due to the injection, it is necessary to have a function of overcoming this pressure and holding the position. Therefore, the hydraulic cylinder diameter and the working hydraulic pressure are determined in consideration of the pressure receiving area and the resin pressure in the mold cavity.
Also, for the boundary between the mold clamping direction and the direction perpendicular to this,
The order of operation of the hydraulic cylinders is important in order to eliminate mutual interference of the movable plates.

The operation sequence of this hydraulic cylinder is shown in FIG.
It will be described based on. Upon receiving the timing signal for moving the movable plates backward, the movable plates 11, 12 are first moved backward by the hydraulic cylinders 21, 22. A little later than this,
The movable plate 13 is retracted by the hydraulic cylinder 23. By this operation, mutual interference of the movable plates can be prevented, and the precision of the mold can be maintained for a long period of time. Next, after holding the gap for a predetermined time, after opening the mold,
Take out the molded product. When the movable plate is moved forward to prepare for the next cycle, the order is reversed.

The structure of the hydraulic cylinder according to the present invention must be of the piston type. A pressure that overcomes the resin pressure is applied to the movable plate before the injection is started, and this load pressure is taken up by the area difference between the piston and the piston rod (the concentric circles of the mold body).

In order to confirm the effect of the present invention, a test for confirming the state of hair fall recovery was conducted using a hot press machine. A woven fabric with a brush made of polyethylene terephthalate (glass point transfer Tg = 69 ° C.) was used as the skin material decorative layer. The test results are shown in Table 1.

As is clear from the experimental results shown in Table 1, when the temperature is raised from the glass transition point Tg or higher of the resin constituting the raised fibers to the temperature of Tg or lower with the load applied to the raised fibers, the deformation is frozen. It becomes permanent distortion (hair fall). However, if the temperature is raised above the temperature at which it is deformed again, the permanent strain (hair fall) is restored.

[Table 1]

The nap during molding is loaded by the molten resin during the mold clamping time. Moreover, since the heat of the core material molten resin is received, once the temperature rises to Tg or higher, the core material resin is cooled to the temperature of Tg or lower as it is. For this reason, it has been impossible to avoid hair collapse in the ordinary injection molding method or the laminating molding method using the press molding method, even if the molding pressure is as low as possible. Further, even if the heat insulation gap is secured by the mold clamping operation as in the present invention, it is difficult to secure the space in the plane parallel to the mold clamping direction, and a satisfactory result is not obtained. However, according to the method of the present invention, the temperature of the core material molten resin during mold clamping, before being cooled to the maximum temperature received by the skin material decorative layer during mold clamping or less, metal contacting the design surface of the skin material Since the mold cavity surface is retracted and a space for heat insulation is provided on the design surface side of the skin material decorative layer, the skin material decorative layer is reheated to a temperature higher than the maximum temperature received during the mold clamping. This will be described with reference to FIG.

In FIG. 4, the temperature received by the skin material decorative layer during mold clamping gradually decreases at a point A at which the maximum temperature is reached, as indicated by the skin material temperature curve. on the other hand,
As shown by the curve of the core material resin temperature, the temperature of the core material resin rapidly decreases from the melting temperature at the time of injection due to cooling of the mold. At time t2 after injection, the movable plate is moved to form a gap between the skin material decoration layer and the mold cavity surface in contact with the skin material. The amount of heat increases from point C to point B. After that, the temperature drop curve becomes the same as the temperature of the core material resin. On the other hand, the time to retract the movable plate is t
When 3 is selected, the temperature of the skin material rises only from the point D to the point E even if the heat insulating gap is provided. This will not allow the skin material to be reheated above the maximum temperature received during mold clamping.

As described above, by selecting the time point when the movable plate is moved between t1 and t3, it is possible to raise the temperature of the skin material to the maximum temperature received by the skin material decorative layer during mold clamping. When the maximum temperature is set to be equal to or higher than the Tg of the skin material decorative layer, the skin material decorative layer can self-recover from the deformed state to the original state by the elastic force.

Further, although the above experiment was carried out when the decorative layer was a raised cloth, the same was true when the decorative layer was a resin sheet or the decorative layer was a skin material lined with a foamed resin. Offense,
By providing the gap, the skin material decorative layer deformed by the resin pressure at the time of mold clamping can be reheated to a temperature higher than the maximum temperature received during molding load and can be restored to the original state without deformation. .

Although the present invention has been described in detail based on the embodiments, it goes without saying that the present invention is not limited thereto. For example, instead of the skin material in which the decorative layer is lined with a foam layer, a material other than resin (such as aluminum foil) may be used in the decorative layer, and a skin material lined with the foam layer may be used. In this case, the damage of the foam layer will be self-recovered. Also, in this embodiment, the movable core on the skin material side of the molded product is retracted to provide a gap as a heat insulating layer between the cavity surface and the skin material, but it is movable on the rear surface of the molded product (opposite skin material side). A space as a heat insulating layer may be provided between the cavity surface and the skin material by arranging the core and retracting the entire bonded product, or these may be combined. In this case, the gate portion at the die cavity inlet is modified so that the skin material penetrates and the core material resin is injected to the opposite gate side. Part of the molded product (gate part) will have a part without the skin material, but this is an effective method depending on the molded product.

Finally, FIG. 3 will be described. FIG. 3 is a flow chart of the forming process of the integral skin laminating and forming. In this figure, the point to be noted is about Ts (measured value of skin material temperature during mold clamping). As is clear from FIG. 4, the temperature of the skin material rises up to the maximum temperature, but drops thereafter. That is, the measured temperature Ts has the same value twice with respect to Ta (set value of the skin material temperature). In the present invention, the movable plate is retracted when the temperature reaches the set temperature Ta while the temperature of the skin material drops after reaching the maximum temperature.

Effects of the Invention Before the temperature of the core material molten resin during mold clamping is cooled to the maximum temperature received by the skin material during mold clamping,
Since the mold cavity surface in contact with the design surface of the skin material is set back to provide a gap for heat insulation on the design surface side of the skin material decoration layer, the temperature of the skin material rises again. That is, the temperature of the skin material is again raised to the maximum temperature or higher received during the mold clamping because the heat release to the mold is blocked by the heat insulating gap and the heat is received from the core material resin. Therefore, the skin material decorative layer that has been deformed by the load pressure during mold clamping is reheated to a temperature of Tg or higher at which the space required for recovery of deformation is secured and the molecular motion of the resin is activated, and the predetermined temperature is reached. By being held for a period of time, the elastic force causes the deformation to self-recover and returns to the original state without deformation. In this case, in the conventional method of moving the entire movable mold by the mold clamping device to secure a gap necessary for recovery of deformation, in the skin material design surface parallel to the mold clamping direction,
It is difficult to secure the gap. In the method of the present invention, since it is possible to secure a gap necessary for recovery of deformation with respect to all skin material design surfaces, it is possible to design the product without any restrictions on the design surface, and to decorate the skin material without surface defects. It can be molded without impairing the texture and texture of the layers.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a bonding molding die, in which a movable core is in an injection standby state.

FIG. 2 is a state in which the movable plate is retracted to form a heat insulating layer in FIG.

FIG. 3 is a flow chart of a forming process for laminating and forming a skin.

FIG. 4 is an explanatory diagram showing a temperature change during molding of the core material resin and the skin material.

[Explanation of symbols]

1 Movable Mold 2 Fixed Mold 3 Skin Material 4 Core Material 11 Movable Plate 12 Movable Plate 13 Movable Plate 21 Hydraulic Cylinder 22 Hydraulic Cylinder 23 Hydraulic Cylinder 31 Movable Core 32 Movable Core 33 Movable Core 100 Bonding Mold Mold Ts / Ts (n-1), Ts (n) Skin material temperature during mold clamping (measured value) Ta Skin material temperature set value ts Cooling time (measured value) ta Cooling time set value

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Claims (3)

(57) [Claims] 1. A skin material having a resin decorative layer as an outermost layer in a mold cavity composed of a movable mold and a fixed mold, or a skin in which the decorative layer is lined with a foamed resin layer. A mold for laminating and molding which integrates a core material with a molten resin by injection molding or press molding to form a skin-bonded resin-molded product. A movable plate in which the mold cavity surface of the movable mold is divided into a plurality of parts. In addition, a movable core is fixed to the surface of the movable plate on the side opposite to the mold cavity, and a working fluid is introduced into the movable core before and after the movable plate so that the movable plate can be moved back and forth. Mold for laminating and molding. 2. A skin-bonding resin in which a skin material having a resin decorative layer as an outermost layer or a skin material in which the decorative layer is lined with a foamed resin layer is integrated with a core material molten resin by injection molding or press molding. In the laminating molding method for molding a molded article, as the decorative layer or the foamed layer, select a material having a glass transition temperature equal to or lower than the maximum temperature that the decorative layer or the foamed layer receives during mold clamping, When the temperature of the molten resin of the core material or the temperature of the skin material reaches a preset temperature during mold clamping, all the movable cores having a cavity surface are retracted so that the cavity surface and the skin material are A laminating and forming method characterized in that a gap is provided between the two. 3. The resin having a gap of 0.05 mm or more when the decorative layer is a resin sheet, and the decorative layer is a woven cloth, a resin-raised woven cloth, or a resin-raised non-woven cloth. In the case of a skin material in which a sheet or a decorative layer is lined with a foamed resin layer, the thickness is 0.5 times or more the thickness of the decorative layer, and the laminating method according to claim 2.